1. Field of the Invention
The invention relates to a method for producing an SiC volume monocrystal and to a monocrystalline SiC substrate.
2. Background of the Invention
The semiconductor material silicon carbide (SiC) is used for high frequency components and for special light-providing semiconductor components because of its excellent physical, chemical, electrical and optical properties, inter alia also as a starting material for power-electronic semiconductor components. SiC substrates (=SiC wafers) with as large a substrate diameter as possible and as high a quality as possible are required for these components.
The basis of the SiC substrates are high-grade SiC volume monocrystals, which are generally produced by physical gas phase deposition, in particular by a sublimation method described, for example, in U.S. Pat. No. 6,773,505 B2 and in German patent DE 199 31 332 C2. The disc-shaped monocrystalline SiC substrates are cut out of these SiC volume monocrystals and are then provided during the manufacture of the components with at least one epitaxy layer in particular also consisting of SiC. The quality of the epitaxy layer decisively depends on the local orientation of the monocrystalline substrate, in other words of the SiC substrate. If local deviations from the optimal orientation occur in the crystal structure of the SiC substrate, this may propagate into the epitaxy layer. The epitaxy layer then also contains local defects, which ultimately can lead to poor properties of the end products, in other words the semiconductor components.